Incore Temperature Monitoring System

The incore nuclear instrumentation system measures neutron flux distribution and  temperatures in the reactor core. The purposes of the incore instrumentation system are to provide detailed information on neutron flux distribution and fuel assembly outlet temperatures at selected core locations. The incore instrumentation system provides data acquisition and usually performs no protective or plant operational control functions.

The incore instrumentation system includes:

  • Incore neutron flux monitoring system
  • Incore temperature monitoring system

Westinghouse Technology Systems Manual, Section 9.2. Incore Instrumentation System. <available from: https://www.nrc.gov/docs/ML1122/ML11223A264.pdf>.

Incore Temperature Monitoring System

The incore temperature monitoring system consists of incore thermocouples, that are positioned at preselected locations to measure fuel assembly coolant outlet temperature for use in monitoring the core radial power sharing and coolant enthalpy distribution. It must be noted coolant outlet temperatures are more or less influenced by lateral flow mixing and for some reactor designs this system has another purpose such as safety functions monitoring. This data (coolant outlet temperatures) may be (depending on certain reactor design) used to:

  1. Provide the operators with indications of inadequate core cooling conditions during emergency situations (e.g. core overtemperature)
  2. Provide information about temperature rise in the fuel assembly. This may indicate a serious core condition (e.g. channel blockage) and should be investigated.
  3. Provide inputs to the subcooling margin monitors
  4. Provide inputs to plant computer computational applications which use core-exit temperatures to determine fuel assembly enthalpy rises and limited power distribution information.

Westinghouse Technology Systems Manual, Section 9.2. Incore Instrumentation System. <available from: https://www.nrc.gov/docs/ML1122/ML11223A264.pdf>.

References:

Radiation Protection:

  1. Knoll, Glenn F., Radiation Detection and Measurement 4th Edition, Wiley, 8/2010. ISBN-13: 978-0470131480.
  2. Stabin, Michael G., Radiation Protection and Dosimetry: An Introduction to Health Physics, Springer, 10/2010. ISBN-13: 978-1441923912.
  3. Martin, James E., Physics for Radiation Protection 3rd Edition, Wiley-VCH, 4/2013. ISBN-13: 978-3527411764.
  4. U.S.NRC, NUCLEAR REACTOR CONCEPTS
  5. U.S. Department of Energy, Instrumantation and Control. DOE Fundamentals Handbook, Volume 2 of 2. June 1992.

Nuclear and Reactor Physics:

  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. W.S.C. Williams. Nuclear and Particle Physics. Clarendon Press; 1 edition, 1991, ISBN: 978-0198520467
  6. G.R.Keepin. Physics of Nuclear Kinetics. Addison-Wesley Pub. Co; 1st edition, 1965
  7. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.
  8. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.
  9. Paul Reuss, Neutron Physics. EDP Sciences, 2008. ISBN: 978-2759800414.

See above:

Incore Instrumentation